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Toward the complete control of brain metastases using surveillance screening and stereotactic radiosurgery
Amparo Wolf1, Svetlana Kvint1, Abraham Chachoua2
1Departments of1Neurosurgery.
Abstract:
OBJECTIVE The incidence of brain metastases is increasing with improved systemic therapies, many of which have a limited impact on intracranial disease. Stereotactic radiosurgery (SRS) is a first-line management option for brain metastases. The purpose of this study was to determine if there is a threshold tumor size below which local control (LC) rates approach 100%, and to relate these findings to the use of routine surveillance brain imaging. METHODS From a prospective registry, 200 patients with 1237 brain metastases were identified who underwent SRS between December 2012 and May 2015. The median imaging follow-up duration was 7.9 months, and the median margin dose was 18 Gy. The maximal diameter and volume of tumors were measured. Histological analysis included 96 patients with non-small cell lung cancers (NSCLCs), 40 with melanoma, 35 with breast cancer, and 29 with other histologies. RESULTS Almost 50% of brain metastases were NSCLCs and commonly measured less than 6 mm in maximal diameter or 70 mm3 in volume. Thirty-three of 1237 tumors had local progression at a median of 8.8 months. The 1- and 2-year actuarial LC rates were 97% and 93%, respectively. LC of 100% was achieved for all intracranial metastases less than 100 mm3 in volume or 6 mm in diameter. Patients whose tumors at first SRS were less than 10 mm maximal diameter or a volume of 250 mm3 had improved overall survival. CONCLUSIONS SRS can achieve LC rates approaching 100% for subcentimeter metastases. The earlier initial detection and prompt treatment of small intracranial metastases may prevent the development of neurological symptoms and the need for resection, and improve overall survival. To identify tumors when they are small, routine surveillance brain imaging should be considered as part of the standard of care for lung, breast, and melanoma metastases. ■ CLASSIFICATION OF EVIDENCE Type of question: prognostic; study design: retrospective cohort; evidence: Class II.
Insights
Stereotactic radiosurgery (SRS) achieves nearly 100% local control for brain metastases smaller than 6 mm or 100 mm³. Early detection via routine brain imaging improves survival for patients with lung, breast, and melanoma metastases.
Area of Science:
- Neurology
- Oncology
- Radiology
Background:
- Incidence of brain metastases is rising due to improved systemic therapies with limited intracranial efficacy.
- Stereotactic radiosurgery (SRS) is a primary treatment for brain metastases.
- Optimal management strategies, including surveillance imaging, require understanding tumor size thresholds for local control.
Purpose of the Study:
- To identify a tumor size threshold for achieving near 100% local control (LC) with SRS.
- To correlate tumor size and LC rates with the utility of routine surveillance brain imaging.
Main Methods:
- Prospective registry analysis of 200 patients with 1237 brain metastases treated with SRS (December 2012 - May 2015).
- Measurement of maximal tumor diameter and volume; histological analysis of common primary cancers (NSCLC, melanoma, breast).
- Median follow-up of 7.9 months and median margin dose of 18 Gy.
Main Results:
- Local progression occurred in 33 of 1237 tumors (median 8.8 months).
- 1- and 2-year actuarial LC rates were 97% and 93%, respectively.
- 100% LC was achieved for tumors < 6 mm diameter or < 100 mm³ volume; smaller tumors (<10 mm or <250 mm³) correlated with improved overall survival.
Conclusions:
- SRS provides excellent local control for small brain metastases (subcentimeter).
- Early detection and prompt SRS treatment of small metastases can prevent neurological symptoms, reduce need for resection, and enhance survival.
- Routine surveillance brain imaging is recommended for lung, breast, and melanoma metastases to facilitate early detection and treatment.
